GB460606A - Improvements in or relating to flexible tubes - Google Patents

Abstract

460,606. Flexible tubes. FREUDENBERG GES., C. Oct. 10, 1935, No. 28010. Convention date, July 15. [Class 99 (ii)] [Also in Group VIII] Flexible tubes impervious to organic solvents, e.g. motor fuels, are prepared by swelling and shredding collagenous material so that the individual fibres are retained, forming the material into tubes, sizing the tubes with gelatine and incorporating in them water insoluble softeners. The disintegrated collagenous material may be formed into threads or bands by extrusion, these being braided or wound on a mandrel, the tube so formed being then coated, e.g. by spraying, with the collagenous material; or tubes so formed may be combined concentrically with tubes made as such by extrusion through an annular die. The tubes are then sized with gelatine solutions by pumping the solution through the tubes in the case of braided tubes or by sizing during winding when thin strips are wound on a mandrel. The tubes are then converted into elastic and water-resistant condition by treatment with softeners such as train oils, castor oil, or paraffin oil. Swelling agents are applied to the tubes before treatment with the softening agents so that they may take up the latter ; suitable agents are glycol, glycerine or mixtures of such with ethyl and methyl alcohol, and the swelling agents are preferably removed before application of the softeners by treatment with organic solvents. After application of the softening agents the tubes are dried in air which results in oxidation of oils such as train oil and castor oil. They are then dried or steamed, washed with organic solvents such as trichlorethylene and again dried. They may be hardened with formaldehyde &c. at the end of the treatments. Specification 313,747, [Class 28 (ii)], is referred to.